Vis Exo
CONVERT — MKV TO MP4
MKV to MP4 Converter, Lossless Where It Can Be
Matroska is the container that holds almost anything — which is precisely why so much software will not touch it. The video inside is very often plain H.264 with AAC audio, so in many cases the conversion is a re-wrap: no re-encoding, no quality lost, finished in about a second.
The Container Is the Problem, Not the Video
Matroska holds more than MP4 can
An MKV can carry several audio tracks, subtitles, chapters and menus. MP4 supports fewer of those, so extra tracks are dropped — and the tool reports that it dropped them rather than quietly handing back a different file.
Lossless when the codecs already match
H.264 video with AAC or MP3 audio goes across untouched. Expect the same quality and roughly the same size as the original.
HEVC and AV1 are the exceptions
Some MKVs use H.265 or AV1, which older MP4 hardware will not decode. Those are re-encoded to H.264, which takes real time, and the page says so before you commit to it.
Size is not an obstacle
There is no upload limit because there is no upload. A multi-gigabyte episode is as easy to feed in as a short clip — the constraint is your device memory, not a server quota.
Three Steps, In Your Browser
- 1
Pick the MKV
Drop it in. The read-out shows the container, the video codec, the audio codec and the duration the tool actually found, rather than assuming.
- 2
Keep MP4 selected
MP4 with H.264 and AAC is the target that plays everywhere. Downscale only if you want a smaller file as well as a different container.
- 3
Watch for dropped tracks
If the MKV had several audio tracks or separate subtitles, the converter reports what it left out, so a missing commentary track is never a mystery.
MKV to MP4 on iPhone, Mac, Windows and Android
The same page works everywhere, with nothing to install. What differs is where the file comes from and where it goes.
iPhone & iPad
iOS cannot play MKV at all. Convert in Safari and the MP4 plays in Photos and Files.
Mac
QuickTime cannot open MKV. Convert it here and it opens in QuickTime, iMovie and Final Cut.
Windows
MKV plays in some Windows players but not in most editors or upload forms; the MP4 works everywhere.
Android
Convert in Chrome for an MP4 that shares cleanly to WhatsApp, Instagram and TikTok.
MP4, WebM, or Keep the MKV?
Three options, honestly compared — including when the right answer is to convert nothing at all.
| Target | Pick it when | Watch out for |
|---|---|---|
| MP4 — H.264 + AAC | A TV, console, phone or editing app that refuses the MKV. | MP4 carries one video track and fewer audio and subtitle layouts, so extras are dropped — this page reports which. |
| Keep the MKV | Archiving, or a player that already handles Matroska. | Nothing to convert: MKV is not broken, it is just less universally accepted. |
| WebM — VP9 + Opus | The MKV holds VP9 or AV1 and is headed for the web. | Re-encodes unless the streams already fit the container. |
MKV to MP4 FAQ
Does converting MKV to MP4 lose quality?
Only if a codec has to change. When the video is already H.264 and the audio is AAC or MP3, the streams are copied into the MP4 container and nothing is re-compressed.
Why does MP4 not support all of my MKV tracks?
The MP4 specification covers one video track and a narrower set of audio and subtitle configurations than Matroska. Multiple audio tracks, separate subtitles and chapters do not all have an MP4 equivalent, so they are dropped.
My MKV has subtitles. Are they kept?
Not as a separate track, in this tool. Subtitles burned into the picture stay, and the page tells you when a subtitle track was dropped instead of silently discarding it.
Can I convert an MKV larger than a gigabyte?
Yes. There is no upload limit, because nothing is uploaded. The real constraint is your device memory, and files around 1GB and above are where a low-RAM phone or tablet can struggle.
Which target should I pick for a television?
MP4 with H.264 and AAC. That combination is what the widest range of televisions, streaming sticks and games consoles will play without transcoding on the fly.
Related Converters
WebM to MP4
Screen recordings and browser captures arrive as WebM, which iPhones and QuickTime will not open. This turns them into H.264 MP4s.
MOV to MP4
QuickTime files that already hold H.264 and AAC are re-wrapped rather than re-encoded — near-instant, with nothing lost.
HEVC to H.264
Modern phones record H.265 to save space, then half the world will not play it. This converts it to H.264, the codec everything decodes.
Compress a Video
Keep the format, drop the resolution and the bitrate — the same engine that converts also makes files smaller.
Convert it, then track something in it
Vis Exo adds blob tracking, pose skeletons, trails, LUT grades and captions to the finished MP4 — free, and entirely in your browser.